(1) Field of the Invention
The present invention relates to a chromatographic method and apparatus for analyzing samples in aqueous solutions containing a plurality of micro-concentration components.
(2) Description of the Prior Art
As the early analytic apparatus of this type, there can be mentioned an amino acid analysis apparatus developed by W. H. Stein and F. Moore in 1951. Then, with development of the high speed liquid chromatographic technique, there have been proposed various analytic apparatuses.
In deionization or ion exchange chromatography, highly ionized samples are separated using an ion exchange resin, and they are quantitatively detected by using, for example, a conductimetric cell.
The system of this type was first developed by Wickbolt [see Z. Anal. Chem., 132, 401 (1951)]. However, in this system, a liquid feed pump is not used and the efficiency of a packed column is low. Accordingly, this apparatus requires a very long time for the analysis and the sensitivity is low.
In the ion chromatograph subsequently developed by Hamish Small, Timothy S. Stevens and William C. Bauman [see Anal. Chem., 47, 1801 (1975)], a high-speed liquid chromatographic technique is utilized and a separating column packed with a pellicular ion exchange gel and a deionizing column are used, whereby high-sensitivity analysis of various ions can be attained.
Ion exchange chromatographs heretofore developed are defective in that the efficiency of separation of ions from one another is low and since the independent liquid feed pump and various connecting members are necessary for regeneration of the deionizing column, the size of the apparatus is inevitably increased and the structure is inevitably complicated.
D. T. Gjerde and J. S. Fritz proposed a method in which the deionizing column is removed from the apparatus of Hamish Small et al. and the remaining system is combined with a large column packed with a wholly porous ion exchange gel, whereby the apparatus is simplified to some extent [J. Chromatogr., 176, 199 (1979)]. According to this proposal, however, the apparatus is still large. Additionally, it has been confirmed that this method is inferior to the above-mentioned method of Hamish Small et al. in the sensitivity.
As will be apparent from the foregoing description, no satisfactory method or apparatus for analyzing a plurality of micro-concentration components present in an aqueous solution has yet been developed, and development of a chromatographic analysis method and apparatus capable of performing analyses at a high efficiency with ease has not yet been achieved.